3D ceramic mold antenna

ABSTRACT

An antenna include a resonator element configured to radiate a wireless signal and a substrate embedding the resonator. The resonator element may be a 3D resonator element. The 3D resonator element may be a helical resonator element.

TECHNICAL FIELD

The subject matter disclosed herein generally relates to wireless charging systems, and in particular, to transmitter antennas that transmitter wireless power signals used to power electronic devices.

BACKGROUND

Wireless charging of batteries of electronic devices has historically been performed by using inductive coupling. A charging base station receiver of an electronic device may have one or more coils in which a current may be applied to produce a magnetic field such that when another coil is place in close proximity, a transformer effect is created and power is transferred between the coils. However, such inductive coupling has a limited short range, such as a few inches or less. Examples of such wireless charging include electronic toothbrushes that are placed on a charging stand and inductive pads inclusive of one or more coils to enable electronic devices with coil(s) to be placed on the pads to be charged.

While inductive charging is helpful to eliminate users having to plug power cords into electronic devices for charging, the limited range at which electronic devices have to be positioned from charging stations is a significant shortcoming of the inductive charging technology. For example, if a user of a mobile device, such as a mobile telephone, is in a conference room without a charging pad or sufficient number of charging pads, then the user is unable to charge his or her phone without a traditional power cord.

Remote wireless charging has recently been developed. Remote wireless charging operates by generating a wireless signal carrying sufficient power that can be directed to charge a battery of an electronic device or to operate the wireless device. Such technology, however, has been limited due to technology advancements being a challenge, as transmitters, receivers, antennas, communications protocols, and intelligence of transmitters have all had to be developed (i) so that sufficient wireless power is able to be wirelessly directed to charge electronic devices and (ii) so that the remote wireless charging is safe and effective for people.

While certain advancements in remote wireless charging have occurred, acceptance of the new technology into homes and businesses (e.g., conference rooms) often requires design elements that extend beyond functionality. As an example, for remote wireless power charging that enables a transmitter to deliver high gain in small areas while avoiding power transmission to other nearby areas, three-dimensional (3D) transmitter antennas may be utilized. However, at frequencies used for the remote wireless charging, the 3D antennas have sufficiently large dimensions (e.g., depth) that consumers and businesses may resist deploying such devices into their homes and offices as a result of undesirable aesthetics and dimensions such as the 3D transmitter antennas extending from a wall on which the transmitters are mounted.

SUMMARY

To provide for transmitter antennas of a transmitter of a remote wireless charging system that are commercially acceptable to consumers and businesses, an antenna may be formed with a resonator element configured to radiate a wireless signal, and a substrate embedding the resonator element. By embedding the resonator element within a substrate having a high permittivity, the dimensions, including length or depth, of the antenna may be reduced. Reduction in antenna dimensions provides for a commercially viable solution in certain environments, such as homes and conference rooms. In one embodiment, the resonator element is helical. The substrate may be ceramic, such as alumina. Wireless signals may include a carrier signal at a frequency greater than 1 GHz. The wireless signals may be circularly polarized when communicated from a helical antenna. Other shaped antennas may produce multi-polarized wireless signals. Embedding the resonator element in a substrate that has high relative permittivity allows for a variety of different antenna types to be utilized and have reduced dimensions.

One embodiment of an antenna may include a resonator element configured to radiate a wireless signal, and a substrate embedding the resonator element. The resonator element may be helically shaped. The substrate may be a ceramic, such as alumina. A core may be disposed inside, and encircled by, the turns of a resonator element that is helically shaped. Multiple antennas may be disposed within a casting, which may be silicon or ceramic, or any other material sharing similar permittivity properties, to form an antenna with multiple antenna elements including resonator elements or resonator elements embedded within a substrate.

One embodiment of a method of manufacturing an antenna may include forming a resonator element configured to radiate a wireless signal, and embedding the resonator element in a substrate. In forming the resonator element, a helical resonator element may be formed.

One embodiment of an apparatus for wirelessly charging a battery may include a transmitter unit that includes a transmitter and an antenna unit in communication with the transmitter. The antenna unit may include multiple 3D antenna elements configured to transmit a wireless signal for use in charging a battery. The battery may be a battery of a mobile device, such as a mobile telephone.

Additional features and advantages of an embodiment will be set forth in the description which follows, and in part will be apparent from the description. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the exemplary embodiments in the written description and claims hereof as well as the appended drawings.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings constitute a part of this specification and illustrate an embodiment of the invention and together with the specification, explain the invention.

FIG. 1 is an illustration of an illustrative wireless power environment in which transmitters are configured to identify locations of one or more receivers inclusive of a 3D transmitter antenna with reduced dimensions, and transmit wireless power signals to those receiver(s) to form energy pocket(s) thereat, according to an exemplary embodiment.

FIG. 2 is an illustration of an antenna, in this case a helical antenna, in which a resonator element is embedded within a substrate, according to an exemplary embodiment.

FIG. 3 is an illustration of an illustrative antenna pattern showing gain of the antenna of FIG. 2, according to an exemplary embodiment.

FIG. 4A is an illustration of a mechanical base of one embodiment of a helical antenna including a helical resonator embedded within a substrate, according to an exemplary embodiment.

FIG. 4B is an illustration of the mechanical base of FIG. 4A inclusive of a helical antenna including a helical resonator element embedded within a substrate, and mounted to the base, according to an exemplary embodiment.

FIG. 5 is an illustration of another illustrative helical antenna with an alternative base, according to an exemplary embodiment.

FIGS. 6 to 12 are illustrations of alternative antenna types that have reduced dimensions as a result of being embedded within a substrate with a high permittivity, according to exemplary embodiments.

FIG. 13 is an illustration of an illustrative antenna unit inclusive of a plurality of antennas inclusive of resonator elements, according to an exemplary embodiment.

FIG. 14 is an illustration of an illustrative antenna unit inclusive of a plurality of antennas embedded within a substrate, according to an exemplary embodiment.

FIG. 15 is a flow diagram of an illustrative process for producing a 3D transmitter antenna inclusive of an resonator element embedded within a substrate, according to an exemplary embodiment.

FIG. 16 is a flow diagram of an illustrative process for producing a transmitter with a 3D transmitter antenna produced using the process of FIG. 14 or FIG. 15, according to an exemplary embodiment.

DETAILED DESCRIPTION

The present disclosure is herein described in detail with reference to embodiments illustrated in the drawings, which form a part here. Other embodiments may be used and/or other changes may be made without departing from the spirit or scope of the present disclosure. The illustrative embodiments described in the detailed description are not meant to be limiting of the subject matter presented here. Alterations and further modifications of the inventive features illustrated herein, and additional applications of the principles of the inventions as illustrated herein, which would occur to one skilled in the relevant art and having possession of this disclosure, are to be considered within the scope of the invention.

Referring to FIG. 1, an illustration of an illustrative wireless power environment 100 in which transmitters 102 a, 102 b (collectively 102) are configured to identify a location of an electronic device 104 with a receiver 106 (or multiple receivers) inclusive of one or more receiver antennas (e.g., cross-polarized dipole antenna), and transmit wireless power signals or waves to the receiver 106 to cause RF signal anti-nodes to form at the receiver 106 is shown. Although shown with multiple transmitters 102, it should be understood that a single transmitter may be utilized. The transmitters 102 each include antenna arrays 108 a, 108 b (collectively 108) inclusive of respective antenna elements 109 a-109 m, 109 n-109 z (collectively 109), and used to transmit wireless power signals 110 a, 110 b (collectively 110). In one embodiment, the antenna arrays 108 a, 108 b have the same number of antenna elements. Alternatively, the antenna arrays 108 a, 108 b have a different number of antenna elements. Still yet, the antenna arrays 108 a, 108 b may have the same or different layouts or configurations of antenna elements. The antenna arrays 108 a, 108 b may have regularly spaced antenna elements or multiple sets of antenna elements with different spacings that are used for different types of transmissions.

Because the transmitters 102 may be positioned in households and commercial settings, such as conference rooms, the transmitters 102 are to be sized in a manner that results in a small footprint and/or profile. Although the size of the footprint (e.g., width of overall antenna arrays) in some cases has to have a certain length for creating small energy pockets at various distances, the profiles (e.g., length of the antenna elements 109 along the z-axis, which defines the distance that the transmitters 102 extend from a wall) can be reduced to be more commercially viable for adoption by consumers and businesses.

The transmitters 102 may also include communication components 112 a, 112 b (collectively 112) that communicate with the electronic device 104. In one embodiment, the receiver 106 may be configured with a transmitter or other circuitry that enables communication with the communication components 112, thereby enabling the transmitters 102 to focus the wireless power signals 110 at the receiver 106 to form an energy pocket 114. The energy pocket 114 may be a localized region at which waves from the wireless power signals 110 form an anti-node (i.e., combined peaks of oscillation signals) that produces a combination of peak signals from each of the wireless power signals 110, as understood in the art.

Because the antenna arrays 108 may have orientations that cause the wireless power signals 110 to be transmitted at different polarizations depending on an orientation of the electronic device with respect to the respective antenna arrays 108, the receiver 106 may include a cross-polarized dipole antenna, for example, so that orientation of the receiver 106 with respect to the antenna arrays 108 has minimal impact in the amount of power that is received from the wireless power signals 110. If the antennas of the antenna arrays 108 are helical, then the wireless signals are circularly polarized, thereby enabling a cross-polarized antenna to be effective.

Referring to FIG. 2, an illustration of an antenna 200, in this case a helical antenna, in which a resonator element 202 is embedded within a substrate 204 is shown. The resonator element 202 is configured in a helical shape with four (4) turns. The dimensions and number of turns is dependent on a frequency range at which the antenna is to operate as well as its desired directivity. In the exemplary embodiment, the antenna operates at frequencies over 1 GHz. However, the antenna can be configured to operate at frequencies in a range from 900 MHz to 100 GHz. More specifically, the center frequency may be about 1 GHz, 5.8 GHz, 24 GHz, 60 GHz, and 72 GHz with bandwidths suitable for operation (e.g., 200 MHz-5 GHz bandwidths), and the dimensions of the antenna and type of antenna may be configured to accommodate the frequencies of operation. The substrate 204 is cylindrical, and configured to embed the resonator element 202 therein. In one embodiment, the substrate 204 is ceramic, where the ceramic may be alumina. The substrate 204 operates as a dielectric, and is more dense than air. The substrate may be any material that provides for a relative permittivity between approximately 9 and approximately 10 at a center frequency of a wireless signal transmitted by a transmitter via the antenna 200. Other relative permittivity ranges may be possible depending upon specifications for the antenna.

A base 206 is shown to include a circular portion that defines a support region 208 in which the substrate may be positioned. The base 206 may also include a connector 208 through which a conductor (not shown) extends to a feed point 210 to feed power signals to the resonator element 202 that is to be transmitted by the antenna 200 to a mobile device, for example, to be charged. The base 206 may operate as a ground plane, as understood in the art, so as to reflect wireless power signals (or limit radiation from projecting below the resonator element 202).

Referring to FIG. 3, an illustration of an illustrative antenna pattern 300 showing gain of the antenna of FIG. 2 is shown. The antenna pattern is shown to range from slightly below −10 dB along the Z-axis (i.e., below the antenna) and up to slightly higher than 8 dB along the Z-axis. Gain levels of upwards of 10 dB or higher may be utilized, as well. For purposes of remote charging, directivity and gain levels may be utilized to ensure that an energy pocket at a receiver is sufficiently small in dimensions with sufficiently high energy such that remote charging of a wireless device may occur. In one embodiment, the directivity is greater than 8 dB. The directivity may be between 8 dB and 10 dB.

Referring to FIG. 4A, an illustration of a mechanical base 400 a of one embodiment of a helical antenna including a helical resonator element embedded within a substrate (see FIG. 4B) is shown. The base 400 a is shown to include a circular support region 402 defined by the base 400 a. A feed point 404 includes an electrical conductor over which power signals may be transmitted. In one embodiment, the power signals may have frequency over 1 GHz, so the feed point 404 and conductors (not shown) that extend thereto are to support such frequencies. The feed point 404 may be adapted to engage or be connected to a helical resonator element, as shown in FIG. 4B. The mechanical base 400 a may be reduced in size from conventional mechanical bases that support helical antennas not embedded within a substrate, as described herein.

Referring to FIG. 4B, an illustration of the mechanical base 400 a of FIG. 4A inclusive of a helical antenna including an antenna or resonator element 406 embedded within a substrate 408,\ and mounted to the base 400 a is shown. As previously described, the substrate may be a ceramic substrate, such as alumina, but could be any other substrate that has a relative permittivity within a specified range that supports reduced dimensions and certain performance of the antenna. In one embodiment, the relative permittivity (i.e., normalized to a vacuum permittivity) is between approximately 9 and approximately 10. Other relative permittivity ranges may be possible depending on the frequencies, gain, antenna pattern, or any other parameter.

As shown, the resonator element 406 may be a helical shaped resonator element. As understood in the art, the helical shaped resonator element is configured to generate a circularly polarized signal. In one embodiment, the support region 402 may be sized to provide for a friction fit for the substrate 408. Alternatively, an adhesive (e.g., glue, epoxy, etc.) or mechanical component (e.g., pin, screw, etc.) may be utilized to secure the substrate 408 inclusive of the resonator element 406 to the mechanical base 400 a. One aspect of the antenna 400 b includes a core 410 positioned radially within the resonator element 406. The core 410 may be a different substrate material than the substrate 408 such that the core 410 has a different permittivity than the substrate 408. In an alternative embodiment, the core 410 is formed by the same material as the substrate 408, and may be formed at the same or different time as the substrate 410. The resonator element 406 may be formed independent from the core 410 or be formed onto the core 410. The resonator element 406 may be a conductive “spring” or be a material (e.g., conductive paint or ink) applied to the core 410. The core 410 provides certain performance improvements over an air core, as understood in the art.

One embodiment for manufacturing the antenna 400 b may include forming a resonator element configured to radiate a wireless signal, and embedding the resonator element in a substrate. As shown in FIG. 4B, the resonator element may be formed in a helical shape, and the substrate 408 may be applied to embed the resonator element 406 therein. In one embodiment, the core 410 may be configured with the resonator element 406 prior to embedding the resonator element 406 within the substrate 408. The substrate 408 inclusive of the resonator element 406 and, optionally, the core 410, may be inserted into the support region 402 of the mechanical base 400 a. In an aspect, the substrate 408 may be affixed or otherwise secured to the mechanical base 400 a using an adhesive or mechanical element, such as a screw. In one embodiment, rather than forming the resonator element 406, the resonator element 406 may be provided to a manufacturer in a preformed manner, and the manufacturer may embed the preformed resonator element 406 within the substrate 408. As a result of the antenna 400 b being reduced in size because of the resonator element 406 being embedded within the substrate 408, the base 400 a may have reduced dimensions than traditional bases. And, because the base 400 a is smaller, more antennas 400 b may be positioned within a smaller footprint, thereby enabling an array of antennas to be smaller (or more antennas within the same footprint) and less costly due to reduced materials used to produce the array of antennas. Moreover, the smaller footprint may be more aesthetically pleasing to a customer of the remote charging system so as to be more commercially viable.

Referring to FIGS. 5 to 12, illustrations of alternative antenna types that have reduced dimensions as a result of being embedded within a substrate with a high relative permittivity are shown. FIG. 5 is a simple rod antenna 500 inclusive of an exciter or resonator 502 and substrate (e.g., ceramic) 504 configured to be positioned within the exciter 502. In operation, the substrate 504 operates as a trapped wave launcher that causes a wireless signal to be trapped within the substrate 504, and produce a more directed antenna pattern with higher gain than the gain when utilizing the substrate 504. The substrate may be mounted to a base 506 for inclusion in another structure, such as a transmitter.

FIG. 6 is an illustration of an illustrative Yagi antenna 600 inclusive of a series of vertically aligned resonators 602 mounted to a substrate 604 configured as a rectangular rod. An alternative shaped substrate 604 may be utilized. Both of the antennas 500, 600 may have a reduced size by being embedded within a substrate (not shown) in the same or similar manner as the antenna 400 b. The substrate may be ceramic, such as alumina. The substrate may be the same or different material than the substrates 504, 604. As with the reduced size of the antennas 500, 600, bases, which may function as ground planes, for the respective antennas 500, 600 may also be reduced in dimension. In one embodiment, the ground planes may be 1.5 square inches or less.

FIGS. 7-12 are illustrations that respectively show different types of illustrative antennas 700-1200, in this case 3D antennas, that may be embedded within a substrate (not shown), and used to provide for remote wireless charging by transmitting wireless power signals to wireless devices from a transmitter. As previously described, the dimensions of the antennas 700-1200 may have smaller dimensions as a result of being embedded within a substrate with a relative permittivity above a certain level. In one embodiment, the relative permittivity may be above 5 in order to achieve significant size reduction in the antenna structure. In another embodiment, the relative permittivity of the substrate may be between 9 and 10. Other levels of relative permittivity may be utilized, as well. It should be understood that while the use of the substrate used for the 3D antennas 700-1200 may provide for reduction in the dimensions of the antennas 700-1200, that the use of a substrate with a 2D antenna may provide for similar reduction in dimensions for the 2D antenna.

FIG. 7 is an illustration of an illustrative Yagi antenna 700 that is printed on a printed circuit board (PCB). FIG. 8 is an illustration of another illustrative helical antenna 800. FIG. 9 is an illustrative tapered antenna 900. FIG. 10 is an illustration of an illustrative multi-level stacked S antenna 1000. Similar to the other mentioned antennas, the antenna shown in FIG. 10 can be molded inside a high-permittivity dielectric. The metallic part of the multi-level stacked S antenna may be a stamped, single piece of metal. FIG. 11 is an illustration of an illustrative miniaturized parabolic antenna 1100, where the parabolic surface is filled with a high-permittivity dielectric. FIG. 12 is an illustration of an illustrative horn antenna 1200. In one embodiment, the horn antenna 1200 may have the substrate (not shown) filled within the horn as opposed to being fully embedded within the substrate (not shown). Alternatively, the entire horn may be embedded within the substrate. The horn may also have a substrate disposed within the horn that is different from another substrate that is used to embed the entirety of the horn inclusive of a substrate within the horn.

Referring to FIG. 13, an illustration of an illustrative antenna unit 1300 inclusive of a plurality of antennas 1302 a-1302 n (collectively 1302) inclusive of resonator elements 1304 a-1304 n (collectively 1304) is shown. The antennas 1302 may be disposed within antenna sub-units 1306 a-1306 n (collectively 1306) defined by unit cells (i.e., periodic shapes) with metallic walls 1308 a-1308 n+1 (collectively 1308) (forming a waveguide or quasi-waveguide structure) that may be formed of metal or other material that may be used to define the antenna sub-units 1306 and limit RF signals to interfere with adjacent antennas. Also defining the antenna sub-units 1306 may be a ground plane 1310 a-1310 n (collectively 1310). Alternative embodiments may not include a ground plane that defines a portion of the antenna sub-units 1306. As part of each of the antenna sub-units 1306 are substrates 1312 a-1312 n (collectively 1312). The substrates 1312 may be the same substrate. Alternatively, different substrate may be used, where the substrate in different antenna sub-units 1306 may have different properties (e.g., different permittivity). The substrates 1312 may be ceramic.

In manufacturing the antenna sub-units 1306, the metallic walls 1308 and ground plane 1310 (or non-ground plane bottom structural component) may be assembled to define the antenna sub-units 1306. The antennas 1302 may be positioned within the assembled metallic walls 1308 and ground plane 1310 that defines the antenna sub-units 1306, and then the substrates 1302 may be poured while in a flowable or injectable state to embed the antennas 1302 and may be allowed or activated to transition to a solid state. Electrical conductors (not shown) may be connected to the antennas 1302 prior to adding the substrates 1312. Although shown as being a linear array, it should be understood that the antenna unit 1300 may be configured as a matrix of antennas 1302, such as the antenna arrays 108 shown in FIG. 1.

Referring to FIG. 14, an illustration of an illustrative antenna unit 1400 inclusive of a plurality of antennas 1402 a-1402 n (collectively 1402) embedded within a substrate 1404 is shown. In one embodiment, the antenna unit 1400 may include a ground plane 1406 that in part shapes an antenna pattern from the antennas 1402. The antennas 1402 collectively provide for an array of antennas such that phasing of wireless power signals transmitted from the array of antennas may enable an antenna pattern to be directed in a phased array antenna pattern, as understood in the art. The antenna unit 1400 does not include waveguide walls, such as the metallic walls 1308, that help to isolate the antennas 1402 from one another to reduce cross-talk. However, the substrate 1404 helps attenuate near field signals to reduce cross-talk between adjacent ones of the antennas 1402. The substrate 1404 that embeds multiple antenna elements may be considered a casting. The substrate 1404 may be a dielectric, such as a ceramic material or silicon material.

Referring to FIG. 15, a flow diagram of an illustrative process 1500 for producing a transmitter antenna inclusive of an antenna element embedded within a substrate is shown. The process may start at step 1502, where a resonator element configured to radiate a wireless signal may be formed. The resonator element may be a 3D antenna, and formed in a variety of different of configurations, as shown in FIGS. 5-12, for example. At step 1504, the resonator element may be embedded in a substrate. In embedding the resonator element in the substrate, the substrate may be applied to the substrate in a flowable or injectable state and transitioned to a solid state. The substrate may start in a powder form and have a liquid solution mixed with the powder to form the substrate. The substrate may have a relative permittivity between 9 and 10. Alternative relative permittivity values may be utilized based on the parameters of the antenna and signal frequencies over which the antenna is to transmit.

Referring to FIG. 16, a flow diagram of an illustrative process for producing a transmitter with a 3D transmitter antenna produced using the process of FIG. 15 is shown. The process 1600 may start at step 1602, where an antenna array inclusive of a plurality of antennas with resonator elements embedded within a substrate may be provided. At step 1604, the antenna array may be connected to a transmitter. The transmitter may be configured to transmit signals greater than 1 GHz, and the antennas of the antenna array may be configured to support frequencies greater than 1 GHz and bandwidths of signals that are used to provide for wireless power signals.

One embodiment of a device for wirelessly charging a battery may include a transmitter unit including a transmitter and an antenna unit in communication with the transmitter. The antenna unit may include multiple 3D antenna elements configured to transmit a wireless signal for use in charging a battery. The battery may be in a mobile device, such as a mobile telephone. Alternatively the wireless signal may be used for operating an electronic device. The 3D antenna elements may be helical. The antenna unit may include a conductive mount socket configured to engage respective 3D antenna elements encasing dielectric rods, the conductive mount socket and antenna elements being inductively coupled to cause a wireless power signal to be transmitted by the antenna elements. The 3D antenna elements may be encased in a dielectric. The dielectric may be ceramic. The dielectric may a relative permittivity of greater than 5. The relative permittivity may be between approximately 9 and approximately 10 at a center frequency of the wireless signal. The wireless signal may have a frequency greater than 1 GHz. In one embodiment, the antenna elements may be stamped metal structures. The stamped metal structures may be configured to transmit the wireless power signal with multiple polarizations. The polarizations may be three.

The antenna unit may be configured as a linear array. The linear array may be longer than 2 feet. The linear array may be formed by multiple linear arrays including a space disposed between the multiple linear arrays. The antenna unit may be configured as a matrix. The 3D antenna elements may be regularly spaced. The antenna elements may be variably spaced. The 3D antenna elements may be grouped into sub-arrays, and the sub-arrays may be selectable for transmitting wireless power signals by the selected sub-arrays. The 3D antenna elements may be individually selectable. A processing unit may be configured to cause a transmitter to generate a signal, and transmit the wireless power signal via the 3D antenna element(s).

The foregoing method descriptions and the process flow diagrams are provided merely as illustrative examples and are not intended to require or imply that the steps of the various embodiments must be performed in the order presented. The steps in the foregoing embodiments may be performed in any order. Words such as “then,” “next,” etc. are not intended to limit the order of the steps; these words are simply used to guide the reader through the description of the methods. Although process flow diagrams may describe the operations as a sequential process, many of the operations can be performed in parallel or concurrently. In addition, the order of the operations may be re-arranged. A process may correspond to a method, a function, a procedure, a subroutine, a subprogram, etc. When a process corresponds to a function, its termination may correspond to a return of the function to the calling function or the main function.

The preceding description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the following claims and the principles and novel features disclosed herein. 

What is claimed is:
 1. An antenna, comprising: a plurality of unit cells configured to radiate radio frequency (RF) power transmission signals, each of the unit cells comprising: a feed point including an electrical conductor; a three-dimensional resonator element configured to radiate a RF power transmission signal provided through the feed point to a wireless-power-receiving device, wherein: the three-dimensional resonator element is helical shaped and includes a plurality of turns, and a frequency and directivity of the RF power transmission signal are based on a number of turns in the plurality of turns; a substrate embedding the three-dimensional resonator element, wherein the substrate is made of a dielectric material; and a wall that surrounds at least a part of the substrate, wherein: the wall is made of a metallic material that is distinct from the dielectric material, and the wall is configured to (i) act as a waveguide or quasi-waveguide structure for the RF power transmission signal to guide it towards the wireless-power-receiving device and (ii) isolate transmission of the RF power transmission signal by a respective unit cell from RF power transmission by neighboring unit cells of the plurality of units cells, and a support base surrounding a bottom portion of the three-dimensional resonator element, the support base operating as a ground plane for the three-dimensional resonator element, wherein at least one substrate included in at least one of the plurality of unit cells has a different permittivity than a remainder of the plurality of unit cells other than the at least one of the plurality of unit cells; and wherein the wireless-power-receiving device converts received RF power transmission signals into usable energy for powering an electronic device coupled to the wireless-power-receiving device.
 2. The antenna according to claim 1, wherein the substrate is cylindrical.
 3. The antenna according to claim 1, wherein the RF power transmission signal has a frequency greater than 1 GHz.
 4. The antenna according to claim 1, wherein the substrate is ceramic.
 5. The antenna according to claim 4, wherein the ceramic is alumina.
 6. The antenna according to claim 1, further comprising a core disposed radially within the three-dimensional resonator element that defines an antenna element.
 7. The antenna according to claim 6, wherein the core is ceramic.
 8. The antenna according to claim 7, further comprising a casting of the substrate embedding a plurality of three-dimensional resonator elements.
 9. The antenna according to claim 8, wherein the casting is silicon.
 10. The antenna according to claim 1, wherein the substrate has a relative permittivity between approximately 9 and approximately 10 at a center frequency of the RF power transmission signal.
 11. The antenna according to claim 1, further comprising a ground plane over which the three-dimensional resonator element extends.
 12. The antenna according to claim 11, wherein the ground plane is less than approximately 1.5 square inches in size.
 13. The antenna according to claim 1, wherein the three-dimensional resonator element embedded within the substrate has a directivity greater than approximately 8 dB.
 14. The antenna according to claim 1, wherein the three-dimensional resonator element embedded within the substrate has a directivity between approximately 9 dB and approximately 10 dB.
 15. The antenna according to claim 1, wherein the three-dimensional resonator element causes the RF power transmission signal to be circularly polarized.
 16. The antenna according to claim 1, further comprising multiple three-dimensional resonator elements embedded within the substrate.
 17. The antenna according to claim 1, wherein the three-dimensional resonator element is disposed on a printed circuit board (PCB).
 18. The antenna according to claim 1, wherein the three-dimensional resonator element is printed on silicon.
 19. A method of manufacturing an antenna, said method comprising: providing a plurality of unit cells configured to radiate radio frequency (RF) power transmission signals, and for each of the unit cells: forming a feed point including an electrical conductor; forming a three-dimensional resonator element configured to radiate an RF power transmission signal provided through the feed point to a wireless-power-receiving device; embedding the three-dimensional resonator element in a substrate, wherein: the three-dimensional resonator element is helical shaped and includes a plurality of turns, a frequency and directivity of the RF power transmission signal are based on a number of turns in the plurality of turns, and the substrate is made of a dielectric material; providing a wall that surrounds at least a part of the substrate, wherein: the wall is made of a metallic material that is distinct from the dielectric material, and the wall is configured to (i) act as a waveguide or quasi-waveguide structure for the RF power transmission signal to guide it towards the wireless-power-receiving device and (ii) isolate transmission of the RF power transmission signal by a respective unit cell from RF power transmission by neighboring unit cells of the plurality of units cells; and providing a support base that surrounds a bottom portion of the three-dimensional resonator element, the support base operating as a ground plane for the three-dimensional resonator element, wherein at least one substrate included in at least one of the plurality of unit cells has a different permittivity than a remainder of the plurality of unit cells other than the at least one of the plurality of unit cells; and wherein the wireless-power-receiving device converts received RF power transmission signals into usable energy for powering an electronic device coupled to the wireless-power-receiving device.
 20. The method according to claim 19, wherein embedding the three-dimensional resonator element in a substrate includes embedding the three-dimensional resonator element in a ceramic substrate.
 21. An apparatus for wirelessly charging a battery, said apparatus comprising: a transmitter including: a plurality of unit cells configured to radiate radio frequency (RF) power transmission signals, each of the unit cells comprising: a feed point including an electrical conductor; a three-dimensional antenna element configured to radiate a RF power transmission signal for use in charging a battery, the RF power transmission signal provided through the feed point to a wireless-power-receiving device, wherein: the three-dimensional antenna element is helical shaped and includes a plurality of turns, and a frequency and directivity of the RF power transmission signal are based on a number of turns in the plurality of turns; a substrate embedding the three-dimensional antenna element, wherein the substrate is made of a dielectric material; a base on which the substrate is positioned, wherein the base operates as a ground plane for the three-dimensional antenna element, and the base surrounds a bottom portion of the three-dimensional antenna element; and a wall that surrounds at least a part of the substrate, wherein: the wall is made of a metallic material that is distinct from the dielectric material, and the wall is configured to (i) act as a waveguide or quasi-waveguide structure for the RF power transmission signal to guide it towards the wireless-power-receiving device and (ii) isolate transmission of the RF power transmission signal by a respective unit cell from RF power transmission by neighboring unit cells of the plurality of units cells, wherein at least one substrate included in at least one of the plurality of unit cells has a different permittivity than a remainder of the plurality of unit cells other than the at least one of the plurality of unit cells; and wherein the wireless-power-receiving device converts received RF power transmission signals into usable energy for powering an electronic device coupled to the wireless-power-receiving device.
 22. The apparatus according to claim 21, wherein the substrate is poured in a flowable state and activated to a solid state to encase the three-dimensional antenna element.
 23. The apparatus according to claim 21, wherein the substrate is ceramic.
 24. The apparatus according to claim 21, wherein the substrate has a permittivity between approximately 9 and approximately 10 at a center frequency of the RF power transmission signal.
 25. The apparatus according to claim 21, wherein the RF power transmission signal has a frequency greater than 1 GHz. 